The present invention relates to fluid controllers wherein a vertical valve stem having an upper end projecting upward from the upper surface of a bonnet is provided with a horizontal pin extending through the upper end, and is movable upward or downward with the upward or downward movement of the horizontal pin to open or close a fluid channel.
FIG. 9 shows such a fluid controller already known. The illustrated fluid controller 51, which is termed a toggle valve, comprises a valve body 52 having a fluid inlet channel 52a facing leftward and a fluid outlet channel 52b facing rightward, a tubular bonnet 53 attached to the upper portion of the valve body 52, a valve stem 54 disposed inside the valve body 52 and the bonnet 53 upwardly and downwardly movably and having an upper end 54a projecting upward from the bonnet 53, a valve disk 56 provided at the lower end of the valve stem 54 for opening or closing the fluid inlet channel 52a with the upward or downward movement of the valve stem 54, a compression coil spring 57 bearing against an outer flange 5b formed on the valve stem 54 close to its lower end and an annular spring retainer 53a provided on the inner periphery of an upper end portion of the bonnet 53 for biasing the valve stem 54 downward, a horizontal pin drive lever 58 having the horizontal pin 55 extending through a base end thereof and pivotally movable about the axis of the pin 55 to a horizontal position (shown in a solid line) or alternatively to a vertical position (shown in a chain line), and an annular lever seat 59 provided on the upper end of the bonnet 53 for the drive lever 58 to bear on. The drive lever 58 has faces 58a, 58b to be in bearing contact with the lever seat 59 which faces are at different distances from the axis of the horizontal pin 55 to move the pin 55 upward or downward.
Stated more specifically, the first bearing face 58a of the drive lever 58 in parallel to the longitudinal direction of the lever is in contact with the lever seat 59 when the drive lever 58 is in the horizontal position indicated in the solid line in the drawing. The second bearing face 58b of the drive lever 58 perpendicular to the longitudinal direction of the lever is in contact with the lever seat 59 when the drive lever 58 is in the vertical position indicated in the chain line in the drawing. The distance from the second bearing face 58b to the axis of the horizontal pin 55 is greater than the distance from the first bearing face 58a to the pin axis, such that the distance between the axis of the pin 55 and the portion of the drive lever 58 in bearing contact with the seat 59 is increased by pivotally moving the drive lever 58 from the horizontal position to the vertical position. This upward movement of the horizontal pin 55 raises the valve stem 54 to open the fluid channel 52a.
With the conventional fluid controller described, the horizontal pin drive lever needs to be pivotally moved to the horizontal position or vertical position against the force of sliding friction between the drive lever and the lever seat. The pivotal movement requires great torque, which is likely to give pain to the hand when the lever is moved to open or close the fluid channel. The sliding friction causes wear on the bearing face of the drive lever in contact with the lever seat, entailing the problem of failing to ensure the full open or closed state. The movement of the drive lever to the horizontal position requires a great space, giving rise to the problem of necessitating an increased space when a plurality of controllers are to be installed.